My invention pertains to circuit fault detection apparatus for railroad track circuit connections. More particularly, the invention relates to apparatus to detect the opening of either of two parallel circuit leads connecting one part of a track circuit system to another part to provide assured circuit connections.
Where operational reliability of an electrical system is desired or a necessity, critical circuit connections subject to damage may be duplicated by parallel wires between connected terminals. This provides circuit continuity if one wire breaks and thus prevents shutdown or failure of the apparatus. A prime example is found in railroad signal systems and particularly at the rail connections from the wayside energy source or train detectors for track circuits. However, if one wire of the parallel pair opens, the circuit is then dependent for operation on the remaining wire. No protection or security remains against system failure if the remaining single wire connection breaks. There is no automatic indication when the one wire breaks since system operation continues. What is needed is an indication of the fault, i. e., an open circuit in one wire of the pair, so that redundant protection against failure can be restored.
Accordingly, an object of my invention is circuit fault detection apparatus for detecting and indicating an open circuit condition in either of a pair of parallel conductors connected between two terminals in an electrical system.
Another object of my invention is an arrangement of apparatus for detecting the failure of either one of duplicate connections between two circuit locations.
Still another object of the invention is circuit fault detection apparatus to check continuity of each of duplicate wire connections between two terminals and to indicate when either connection opens.
A further object of my invention is apparatus for detecting and indicating a fault in either one of two parallel connections between track circuit wayside apparatus and one rail of the corresponding track section.
Yet another object of the invention is circuit fault detection apparatus for determining the continuity of each of duplicate connectors between points on one common conductor and points on a second common conductor.
Other objects, features, and advantages of my invention will become apparent from the following description and appended claims when taken with the accompanying drawing.